Plug-in connector for connecting two flat strip conductors and associated plug-in connector system

ABSTRACT

The invention relates to a plug-in connector for connecting two flat strip conductors, including at least one spring element which provides the required normal contact power for the connection of the two flat strip conductors. The spring element contacts the two flat strip connectors and produces the electric contact between the two flat strip connectors.

The present invention relates to a plug connector for connecting tworibbon conductors as well as a plug connector system.

Ribbon conductors are finding an ever broader field of application inmany fields of technological use, because, with them, it is possible toconstruct, in a simple way, preformed wiring sets that can be installedsimply and rapidly during assembly. One field of application of theseribbon conductors is increasingly the motor vehicle industry, because,owing to the use of many electronic components in vehicles, theresulting flows of current are becoming increasingly large. The largerconductor cross section required for a larger current flow can beaccommodated in the case of ribbon conductors by the width of theconductive track.

When two ribbon conductors are connected, among other things, springelements are used, which are arranged in such a way that they afford thenormal contact force between the two ribbon conductors required for thecontact.

Known from FR A 1,236,251 is a plug connector for connecting two ribbonconductors, wherein each ribbon conductor is held in place in arespective holder, which has a spring element by means of which theribbon conductor is clamped. In this plug connector, however, each ofthe ribbon conductors stripped of insulation lies on its respectiveholder with its contact surface exposed.

Known from DE 198 32 011 A1 is a junction region for connecting tworibbon conductors, in which one of the ribbon conductors is arranged inthe interior of the housing of this junction region around a holder thatcan be shifted in the housing. This holder has spring elements thatpress one ribbon conductor against the other ribbon conductor in orderto produce the requisite normal contact force. This junction region iscomplicated and costly in terms of its overall construction with itsshiftable holder, because an adjusting mechanism that can pivot andproduces the requisite normal contact force is provided.

Of crucial importance for good electrical contact is the contactresistance between the two ribbon conductors at the contacting site aswell as the normal contact force exerted at this contacting site.Depicted in FIGS. 1 and 2 are the curves of measurements, carried out bythe applicant, that are concerned with these crucial decision-makingparameters.

Plotted in FIG. 1 is the contact resistance between two conductivetracks as a function of the normal contact force applied for a flexibleribbon conductor with a thickness of 200 μm. As is evident from thisfigure, the contact resistance is constant starting from a normalcontact force of approximately 2 N and does not become any smaller. Itcan be concluded from this that a normal contact force of ≧2 N minimizesthe contact resistance between two conductive tracks. Plotted in FIG. 2is the plastic deformation of conductive tracks of 100 μm and 200 μmthickness that results when a test ball with a diameter of 2 mm ispressed with a certain test force on the stripped bare copper conductivetrack. As is evident from the two measurement curves represented, thereresults a detectable plastic deformation for a ball diameter of 2 mmonly above a force of approximately 2 N at a conductor thickness of 100μm and only above a force of 4 N at a conductor thickness of 200 μm. Itcan be concluded from the measurement curves shown in FIGS. 1 and 2 thatthe connection of two ribbon conductors is readily possible given aproper placement of the contact sites and that the normal contact forceshould lie at approximately 2 to 4 N depending on the thickness of theconductive tracks.

The object of the present invention is to create a connection betweentwo ribbon conductors that fulfills the above requirements of normalcontact force and that, at the same time, has a simple andcost-effective construction and makes possible a simple connectionbetween the two conductors.

This object is fulfilled by a plug connector in accordance withindependent patent claim 1.

This object is also fulfilled by a plug connector system in accordancewith claim 10.

In accordance with the invention, the plug connector for connecting tworibbon conductors has at least one spring element, which affords therequisite normal contact force for the connection of the two ribbonconductors, the spring element contacting the two ribbon conductors andproducing the electrical connection between the two ribbon conductors.Owing to the fact that the spring element contacts the two springelements¹ directly, it is possible, through the construction of thespring element, to adjust the requisite normal contact force in a simpleway.[Translator's Note]: sic; presumably, “the two ribbon conductors” ismeant.

In a preferred embodiment, the spring element is joined in a fixedmanner to the first ribbon conductor; for example, it can be soldered inplace on the first ribbon conductor. Here, the first ribbon conductor ispreferably arranged on a printed circuit board, the ribbon conductorforming the conductive tracks of the circuit board.

Furthermore, the plug connector can have an uptake for an inserted uniton which the second ribbon conductor is held in place. This insertedunit with the ribbon conductor held in place on it is inserted into theplug connector so that the spring element can contact the conductivetracks of the second ribbon conductor when the latter is inserted intothe plug connector.

Preferably, the uptake has channels, which are separated from oneanother by ribs and in each of which a spring element is arranged.Through this arrangement, it is possible to arrange the spring elementsused for the electrical connection in a simple way in the uptake.

Furthermore, the spring element preferably has a free end, which is bentback in the direction of insertion of the inserted unit. When theinserted unit, with the second ribbon conductor held in place on it, isinserted, the spring element touches the contact surface of the secondribbon conductor stripped of insulation.

Furthermore, the inserted unit can have a raised part in the directionof insertion in front of the spring element, this raised part forming astop for the spring element. At the same time, when the inserted unit isnot inserted, this raised part affords a protection for the springelement in the uptake, because, when the plug connector is arranged onthe circuit board with the ribbon conductor, the spring element ispoorly accessible from the outside and thus cannot be bent or damaged.

In a preferred embodiment, the inserted unit has, once again, a ribbedstructure, in which the spring element engages and contacts the secondribbon conductor held in place on the inserted unit. The spring elementis guided by this ribbed structure during insertion of the inserted unitinto the plug connector and a successful contacting between the springelement and the second ribbon conductor is ensured. Owing to the ribbedstructure, the contact region of the second ribbon conductor is alsoprotected against damage due to improper use by a user when the insertedunit does not yet lie in the plug connector and the contact region ofthe second ribbon conductor would otherwise by freely accessible andunprotected.

The problem of the invention is further solved by a plug connectorsystem for connecting two ribbon conductors, which has a first holder,on which the first ribbon conductor is held in place, and a secondholder, on which the second ribbon conductor is held in place and whichhas a spring element that affords the requisite normal contact force forconnecting the two ribbon conductors. The first holder has, inaccordance with the invention, a comb structure, the first ribbonconductor being laid around teeth of the comb structure that engagebetween the ribs formed on the second holder and thus connect the tworibbon conductors with each other. This arrangement affords a secure andsimple connection of the individual conductive tracks with the requisitenormal contact force.

Preferably, the at least one spring element is arranged each time in atleast one recess formed in the second holder. Furthermore, the secondribbon conductor can be arranged between the spring element arranged inthe recess and the ribs, so that the spring element presses the secondribbon conductor against the ribs. The ribbon conductors lying aroundthe teeth of the comb structure each engage between two ribs and contactthe ribbon conductor that is pressed from below by the spring elementagainst the ribs. In this way, a non-slipping, simple contacting of theribbon conductors is achieved.

Preferably, one conductive track of the first ribbon conductor liesaround each tooth of the comb structure, a shoulder for guiding therespective conductive track being formed between the teeth.

In order to hold in place the first ribbon cable in the first holder,the latter has a cross piece running transverse to the conductive tracksand a hinge that can swing from a prelocking position to a final lockingposition, this hinge at the same time holding in place the end of theribbon cable in the final locking position. In this way, it is possibleto lay the end of the ribbon cable stripped of insulation around theteeth of the comb structure in a simple manner and, at the same time, toachieve a strain relief for the cable, which arises owing to the factthat the cable is held in place between the cross bar and the hinge.

Provided in a preferred embodiment between every two ribs of the secondholder is a respective spring element, and each of these presses aconductive track of the second ribbon conductor in the direction of thefirst ribbon conductor placed around the teeth. Achieved in this way isthe optimal normal contact force for each individual conductive track.

The invention will be described in detail below with reference to theattached drawings.

FIGS. 1 a and 1 b show the relation between the contact resistance andthe normal contact force for the connection of two conductors as well asthe penetration depth of a test ball for two different conductorthicknesses as a function of the applied force;

FIG. 2 shows an oblique view of a plug connector according to a firstembodiment of the invention;

FIGS. 3 a and 3 b show the inserted unit of the plug connector used inFIG. 2 in a pre-locked position and in a final locked position;

FIG. 4 shows a plug connector system of the invention in an obliqueview;

FIG. 5 shows a the plug connector system of FIG. 4 in a plan view;

FIG. 6 shows a section along A-A of FIG. 5;

FIG. 7 shows a section along B-B of FIG. 5;

FIGS. 8 a and 8 b show a holder of the plug connector system of FIG. 5in a view at an angle from above and at an angle from below;

FIG. 9 shows the holder of FIG. 8 without ribbon conductor;

FIG. 10 shows a section along B-B of FIG. 8 b;

FIG. 11 shows a detailed view of FIG. 10;

FIG. 12 shows a second holder with ribbon conductor, which is used forthe plug connector system of FIG. 5;

FIGS. 13 a and 13 b show the housing as well as the base piece of theholder shown in FIG. 12;

FIG. 14 shows a section along a conductive track through the holder ofFIG. 12; and

FIG. 15 shows a detailed view of FIG. 14.

FIG. 2 shows a plug connector 10, which connects a first conductor 12 toa second conductor 11. The second conductor 11, in the present example,is a flexible ribbon conductor and the conductor 12, in the presentexample, is arranged on a circuit board 13. The second conductor 12 doesnot necessarily need to be arranged on a circuit board, but can also bearranged on any other support, which, in the present embodiment example,is preferably rigid. The plug connector 10 has a housing 14 with anopening 15, which forms an uptake for an inserted unit 16 (see FIGS. 3 aand 3 b), which can be attached by means of a catch 17 on the housing 14of the plug connector 10. The inserted unit further has a coding 18 sothat the inserted unit is not inserted into the housing from the wrongside.

As is evident in FIG. 3 a, the inserted unit 16 has a housing 19 made ofinsulating material, on the top side of which a ribbed structure 20 isformed. The second ribbon conductor 11 is inserted with its conductivetracks 21, which have been stripped of insulation at the front end, upto a terminal stop 22 into the housing 19 and held in place therein by aretaining plate 23.

Represented in FIG. 3 a is the retaining plate in the pre-lockedposition. It has catches (not shown), with which it is positioned ongrooves 24 formed on the housing 19.

Represented in FIG. 3 b is the retaining plate 23 in the final lockedposition, the conductive tracks 21 now being pressed by the retainingplate 23 from below against the ribbed structure 20. The ribbedstructure 20 forms, at the same time, a protection of the conductivetracks stripped of insulation, because, owing to handling by a user,these tracks cannot be touched and thereby cannot be contaminated ordamaged. In the final locked position, the retaining plate 23 with thehousing 19 at the back end forms a strain relief 25 for the secondribbon conductor 11. As represented in FIG. 2, the inserted unit 16 isnow inserted into the housing 14 of the plug connector 10, whereby aspring element 27 arranged in fixed position on the conductive track 26of the first ribbon conductor 12 electrically connects the firstconductor 12 with the second conductor 11. The spring element can, forexample, be soldered on the first conductor 12. The spring element isarranged in channels 29 of the housing 14, these channels being formedby ribs 28, the free end 30 of the spring element 27 being bent back andforming the contact surface with the ribbon conductor 11. The channel 29formed for receiving the spring element 27 is bounded at the front endby a raised part 31, which forms a stop for the spring element 27 and,at the same time, when the inserted unit 16 is not inserted, affords aprotection for the spring element.

The plug connector represented in FIGS. 2 and 3 affords a plug connectorwith good long-term stability, for which, owing to the construction ofthe spring, the requisite normal contact force is achieved with lowcontact resistance. The plug connector is also easy to manufacture,because the ribbon cable stripped of insulation has to be inserted onlyup to the terminal stop 22, the retaining plate has to be brought intoits final locked position of FIG. 3 b, and the inserted unit, togetherwith the ribbon conductor, has to be inserted into the housing 14 of theplug connector 10. These operating steps can all be fully automated,this making the plug connector simple to manufacture. Furthermore, therequisite normal contact force is readily adjusted by the bending of thespring. In the non-inserted state of the inserted unit 16, the free end30 of the spring element 27 normally projects above the raised part 31,so that the spring element in the embodiment represented in FIG. 2 ispre-tensioned. The spring element 27 can also take a different geometricform; a region of the spring element need only project above the raisedpart 31 when the inserted unit 16 is not inserted and contact theconductive tracks of the inserted unit in the inserted state.

Represented in FIG. 4 is an embodiment of a plug connector system 50 inaccordance with the invention. The plug connector system 50, in theembodiment presented, connects a first ribbon conductor 51 to a secondribbon conductor 52. The first ribbon conductor 51 is held in place on afirst holder 60 and the second ribbon conductor 52 is arranged on asecond holder 80 in the housing 53 of the plug connector system.

Represented in FIG. 5 is a plan view of the plug connector system 50.Represented in FIG. 6 is a section along the line A-A of FIG. 5 betweentwo conductive tracks of the plug connector system. The first ribbonconductor 51 is placed around the first holder 60, which is inserted, asrepresented in FIG. 6, from the left into the housing 53 of the plugconnector system 50.

The first holder 60 is represented in FIGS. 8 to 11 and has a base piece61, which has, on both sides, spring arms 62 with projections 63, withwhich the first holder 60 is held in place in the housing 53 of the plugconnector system 50. As represented in FIG. 9, teeth 64 of a combstructure 65 are formed on the base piece 61, around which, as shown inFIG. 8 a and FIG. 8 b, the conductor is laid. The teeth 64 are arrangedin such a way that one respective conductive track of the ribbonconductor 51 can be laid around each tooth. As represented in FIG. 8 b,the comb structure 65 has shoulders 66 on its bottom side, theseshoulders being formed as elongated projections, with which therespective conductive tracks are guided on the teeth 64.

Represented in FIG. 10 is a section along the line B-B of FIG. 8 b. Theribbon conductor 51 runs from the left and is held in place between across piece 67 and a cover 68, which locks with the base piece 61laterally via catches (not shown). This cover 68 is, as represented inFIG. 11 in enlargement, arranged via a hinge 69 in a swinging manner.For introduction of the ribbon conductor 51, the hinge is open and thecover 68 is in an upper position, so that the ribbon conductor can beguided over the cross piece 67 around the teeth 64 before the end of theribbon conductor 51 can be held in place by a fixing element 70. Whenthe cover 68 is closed, a lip 71 of the cover 68 forms a stop, whichpresses the fixing element 70 with the ribbon conductor 51 lying inbetween against the tooth 64 and thus holds the ribbon conductor firmlyin place in the first holder 60. The ribbon conductor 51 is stripped ofinsulation in the region in which it is placed around the teeth 64 ofthe comb structure 65.

Represented in FIG. 6 is the section along A-A of FIG. 5 between twoconductive tracks through the plug connector system 50. In FIG. 7, insection B-B of FIG. 5, this section is represented along a conductivetrack of the two ribbon conductors 51, 52. The conductor 51, held inplace by the cross piece 67 and the cover 68, which serve as strainrelief, goes around the tooth 64 of the comb structure 65 and contactsthe second ribbon conductor 52 laid around the second holder 80.

The second holder 80 is represented in FIGS. 12 to 15. The second holder80 has a housing 81, which corresponds essentially to the housing 19 ofthe inserted unit 16 represented in FIG. 3 a. The housing 81 (see FIG.13 a) has, on its two long sides, a catch 82, with which it is attachedto the housing 53 of the plug connector system 50. Likewise, it has ribs83 and grooves 84, in which catch shoulders 85 engage, which are formedon a base piece 86 of the second holder at various heights for apre-locked position and final locked position. The base piece 86 forms aholder for the second ribbon conductor 52, which is stripped ofinsulation at its front end, so that the conductive tracks 54 form thecontact region. Arranged to guide the individual conductive tracks 54are flanks 87, formed lengthwise on the base piece 86. The base piecerepresented in FIG. 13 b is clicked onto the housing 81 and can be movedbetween a pre-locked position and a final locked position, which aredefined by the different height of the catch shoulders 85 on the basepiece 86.

As represented in FIG. 14, the base piece 86 has recesses 88, in each ofwhich a spring element 90 is arranged. As represented in FIG. 15 inenlargement, the spring element 90 lies on the bottom 91 of the recess88, is bent back, and terminates in a free end 93, which presses theribbon conductor 52 from behind with its contact surface 92 against theribs 83. The force with which the ribbon conductor 52 is pressed againstthe ribs 83 is influenced by the selection of the spring geometry aswell as the choice of materials of the spring element 90. The springfurther has, at its free end 93, a semicircular bend 94, which stops themovement of the free end downward when the bend 94 comes to rest on thelower part of the spring element.

As represented in FIG. 7, the teeth 64, surrounded by the first ribbonconductor 51, engage between the ribs 83 of the second holder 80 andpress the stripped first ribbon conductor 51 with the contact surfacethereof 72 against the contact surface 92 of the ribbon conductor 52,which is pressed by means of the spring element 90 against the ribs 83.

By means of the geometric selection of the teeth and the choice of thespring geometry and material of the spring element 90, it is possiblethen to adjust the plug connector system in such a way that the desirednormal contact force lies between 2 and 4 N, so that an optimalcontacting with low contact resistance results, while the penetrationdepth into the conductor is not so large that the latter is damaged.

Preferably, the second holder is constructed in such a way that, foreach conductive track 54, there is provided a recess 88 with a springelement 90, the spring element 90 pressing the conductor 52 between tworibs 83.

A repeatedly releasable system, for which conductive tracks of variousribbon conductors can be connected with good contact resistance andsmall spatial requirement is made available by means of the present plugconnector system. For example, the second holder can be modified in sucha way that the conductive tracks of the second ribbon conductor have adiffering width. Overall, a contact with defined contact force isachieved through two simple insertion motions of the two holders.

1. A plug connector for connecting two ribbon conductors, which has atleast one spring element that affords the requisite normal contact forcefor connecting the two ribbon conductors, is hereby characterized inthat the spring element contacts the two ribbon conductors and producesthe electrical connection between the two ribbon conductors.
 2. The plugconnector according to claim 1, further characterized in that the springelement is joined solidly with the first ribbon conductor.
 3. The plugconnector according to claim 1, further characterized in that the plugconnector has an uptake for an inserted unit, on which the second ribbonconductor is held in place.
 4. The plug connector according to claim 3,further characterized in that the uptake has channels that are separatedfrom one another by ribs, in each of which a spring element is arranged.5. The plug connector according to claim 3, further characterized inthat the spring element has a free end, which is bent back in thedirection of insertion of the inserted unit.
 6. The plug connectoraccording to claim 5, further characterized in that, in the direction ofinsertion in front of the spring element, the inserted unit has a raisedpart, which forms a stop for the spring element.
 7. The plug connectoraccording to claim 5, further characterized in that the free end of thespring element touches the second ribbon conductor held in place on theinserted unit.
 8. The plug connector according to claim 3, furthercharacterized in that the inserted unit has a ribbed structure, in whichthe spring element engages and contacts the second ribbon conductor heldin place on the inserted unit.
 9. The plug connector according to claim1, further characterized in that the first ribbon conductor is arrangedon a circuit board.
 10. A plug connector system for connecting tworibbon conductors, with a first holder, on which the first ribbonconductor is held in place, a second holder on which the second ribbonconductor is held in place, which has at least one spring element thataffords the requisite normal contact force for connecting the two ribbonconductors, is hereby characterized in that the first holder has a combstructure, whereby the first ribbon conductor is placed around teeth ofthe comb structure, which engage on ribs formed on the second holder andthus connect the two ribbon conductors to each other.
 11. The plugconnector system according to claim 10, further characterized in that atleast one spring element is arranged in at least one recess formed inthe second holder.
 12. The plug connector system according to claim 11,further characterized in that the second ribbon conductor is arrangedbetween the spring element, arranged in the recess, and the ribs, sothat the spring element presses the second ribbon conductor against theribs.
 13. The plug connector system according to claim 10, furthercharacterized in that a conductive track of the first ribbon conductorlies around each tooth of the comb structure, a shoulder being formedbetween the teeth for guiding the respective conductive tracks.
 14. Theplug connector system according to claim 10, further characterized inthat the ribbon conductor in the first holder is held in place between across piece that runs transverse to the conductive tracks and a hinge,which can be swung from a prelocking position into a final lockingposition and which, at the same time, holds the end of the ribbonconductor in the final locking position.
 15. The plug connector systemaccording to claim 10, further characterized in that a respective springelement is provided between two ribs, which presses a respectiveconductive track of the second ribbon conductor in the direction of thefirst ribbon conductor laid around the teeth.